CN117906826A

CN117906826A - Differential pressure sensor

Info

Publication number: CN117906826A
Application number: CN202311641014.7A
Authority: CN
Inventors: 王小平; 曹万; 杨军; 王红明; 刘苹; 贺方杰; 梁世豪; 施涛
Original assignee: Wuhan Finemems Inc
Current assignee: Wuhan Finemems Inc
Priority date: 2023-11-30
Filing date: 2023-11-30
Publication date: 2024-04-19

Abstract

A low cost differential pressure sensor, comprising: a first housing provided with two pressure introduction ports for introducing a pressure medium at right and left intervals; a second housing downwardly sealingly connected to the first housing and defining a mounting cavity therewith; the lower side of the base body is enclosed with the first shell to form two diaphragm component mounting cavities respectively corresponding to the two pressure introduction ports downwards, the upper side of the base body and the second shell enclose an electronic module component mounting cavity, two through holes which are communicated with the upper surface and the lower surface of the second shell and are arranged in one-to-one correspondence with the two pressure introduction ports are formed in the base body, and the lower end of one through hole is enlarged to form a first concave cavity; two diaphragm assemblies; an electronic module assembly disposed within the electronic module mounting cavity; the two ends of the connecting pipe are respectively communicated with the upper ends of the two through holes in a sealing way; a pressure chip fixed to the first cavity; a plurality of connection terminals.

Description

Differential pressure sensor

Technical Field

The application relates to the technical field of pressure sensors, in particular to a differential pressure sensor.

Background

The differential pressure sensor is a sensor for measuring the difference between two pressures. CN113029430a discloses a differential pressure sensor mainly used for an EGR (Exhaust Gas recirculation) system, which introduces pressure to a pressure sensing surface on the opposite side of a pressure chip through two metal diaphragms and silicone oil, the pressure chip is disposed in an upper wall cavity of one pressure introduction port, and the other pressure introduction port extends to the pressure chip through a transverse connecting channel. The connection channels are usually less than 2mm due to the need for miniaturization of the sensor, while on the other hand, due to pressure connections and the limitation of the membrane dimensions, their lateral dimensions are more than 30 mm, with aspect ratios as high as 15 or more. Such large aspect ratio holes are difficult to machine and costly to produce.

Disclosure of Invention

Aiming at the defects of the prior art, the application provides a differential pressure sensor which is used for avoiding processing the hole with the large length-diameter ratio, thereby reducing the manufacturing difficulty and the production cost.

In order to achieve the above purpose, the present application provides the following technical solutions: a differential pressure sensor, comprising:

A first shell body provided with two pressure introduction ports which are used for introducing pressure medium and are spaced left and right;

A second housing downwardly sealingly connected to the first housing and defining a mounting cavity therewith;

the lower side of the base body is enclosed with the first shell to form two diaphragm assembly mounting cavities which respectively correspond to the two pressure introduction ports downwards, the upper side of the base body and the second shell are enclosed to form an electronic module assembly mounting cavity, two through holes which are communicated with the upper surface and the lower surface of the second shell and are arranged in one-to-one correspondence with the two pressure introduction ports are formed in the base body, and the lower end of one through hole is enlarged to form a first concave cavity;

The two diaphragm assemblies are arranged in the two diaphragm assembly mounting cavities in a one-to-one correspondence manner, and comprise a metal diaphragm, a cavity is defined between the metal diaphragm and the second shell, the upper side of the cavity is correspondingly communicated with the through hole, and the metal diaphragm is hermetically separated between the lower side of the cavity and the pressure inlet;

An electronic module assembly disposed in the electronic module mounting cavity and connected to an external device through a plurality of connector terminals fixed to the second housing;

the two ends of the connecting pipe are respectively communicated with the upper ends of the two through holes in a sealing way, and the cavity, the through holes, the first concave cavity and the inner cavity of the connecting pipe are communicated to form a pressure guide liquid filling space;

The pressure chip is fixed at the lower end of the corresponding through hole, and partitions the pressure guide liquid filling space into a first part and a second part, the first part and the second part are respectively communicated with the lower end of a pressure guide liquid injection hole, and a sealing body is blocked at the upper end of the pressure guide liquid injection hole;

and the lower ends of the connecting terminals pass through the seat body in a sealing way and then extend into the first concave cavity to form electric connection with the pressure chip, and the upper ends of the connecting terminals are electrically connected to the electronic module assembly.

Preferably, the upper end of the through hole is enlarged to form a recess, and both ends of the connection pipe are correspondingly welded to the bottom of the recess and surround the upper end of the through hole.

Preferably, the connection pipe includes vertical portions at both ends and a middle portion connecting the two vertical portions, the middle portion having an elastic portion providing a certain elasticity for left and right stretching.

Preferably, the intermediate portion extends in a horizontal plane.

Preferably, the elastic portion is serpentine.

Preferably, at least one of both ends of the connection pipe is outwardly expanded to form an expansion part, and an outer edge of the expansion part is welded to the seat body.

Preferably, the expansion part is a flat soldering lug.

Preferably, the expansion portion is a conical lug, and the radius of the lower end of the conical lug is larger than that of the adjacent part.

Preferably, the pressure-guiding liquid injection hole is formed on the conical soldering lug.

Preferably, the diaphragm assembly further comprises a diaphragm mounting base, the side wall of the diaphragm mounting base is connected to the side wall of the second concave cavity formed at the bottom of the base in a sealing manner, and the periphery of the diaphragm mounting base is connected to the metal diaphragm on a circle of convex rings formed by downward protruding of the diaphragm mounting base in a sealing manner; a cavity is defined between the metal diaphragm and the diaphragm mounting base body, and each cavity is communicated with the lower end of the corresponding through hole through a hole formed in the diaphragm mounting base body.

Drawings

FIG. 1 is a schematic diagram of a differential pressure sensor according to a preferred embodiment of the present invention;

FIG. 2 is a perspective cross-sectional view of a connection pipe according to a preferred embodiment of the present invention;

Reference numerals illustrate: 12b, connector terminals; 13. a bushing; 1 a, a first seal groove; 1. a second housing; 21. a pressure introduction port; 2a, a second sealing groove; 2b, a first sealing flange; 2. a first housing; 30a, through holes; 31. a sealing body; 32. a pressure-guiding liquid injection hole; 33a, a recess; 33b, a recess; 34. a top; 3a, a second sealing flange; 3b, a first concave cavity; 3c, a second concave cavity; 3. a base; 40b, pressure guiding liquid; 41. a metal diaphragm; 42. a compression ring; 43a, holes; 43b, flaring; 43. a diaphragm mounting base; 4a, a chamber; 4b, a chamber; 4. a diaphragm assembly; 5. filling blocks; 6. a pressure chip; 71. connecting leads; 72a, glass seeds; 72. a connection terminal; 73. a hard circuit board; 74a, a flexible circuit board; 74b, a flexible circuit board; 75. an electronic component; 7. an electronic module assembly; 81. an elastic part; 82. a soldering lug; 83. a soldering lug; 8a, one end; 8b, the other end; 8. a connecting pipe; 9. and (5) jointing the pipes.

Detailed Description

The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. The following examples are illustrative only and are not to be construed as limiting the application. In the following description, the same reference numerals are used to designate the same or equivalent elements, and duplicate descriptions are omitted.

In the description of the present application, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships in which the product of the present application is conventionally put in use, or the directions or positional relationships in which those skilled in the art conventionally understand are merely for convenience of describing the present application and for simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be construed as limiting the present application.

In addition, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood as appropriate by those of ordinary skill in the art.

It should be further understood that the term "and/or" as used in the present description and the corresponding claims refers to any and all possible combinations of one or more of the listed items.

As shown in fig. 1. A preferred embodiment of the differential pressure sensor of the present application comprises: a first housing 2, a second housing 1, a housing 3, two diaphragm assemblies 4, an electronic module assembly 7, a connecting tube 8 and a pressure chip 6. The first housing 2 is provided with two pressure inlets 21 for introducing a pressure medium at right and left intervals. The second housing 1 is connected to the first housing 2 in a downward sealing manner and encloses a mounting cavity (not labeled) with the first housing 2, and illustratively, a circle of first sealing grooves 1a are formed at the lower part of the second housing 1, the periphery of the first housing 2 correspondingly protrudes upward to form a circle of first sealing flanges 2b, and the first sealing flanges 2b are inserted into the first sealing grooves 1a and are bonded and sealed by sealant. The seat body 3 is connected to the first housing 2 in a downward sealing manner and is disposed in the mounting cavity, illustratively, two circles of second sealing grooves 2a are formed on the first housing 2, the second sealing grooves 2a are located on the inner side of the first sealing flange 2b, the periphery of the seat body 3 correspondingly protrudes downwards to form two circles of second sealing flanges 3a, the two circles of second sealing flanges 3a correspondingly insert into the second sealing grooves 2a and are bonded and sealed through sealant, and therefore, the lower side of the seat body 3 and the first housing enclose two diaphragm assembly mounting cavities corresponding to the two pressure inlet openings 21 respectively downward, the upper side of the diaphragm assembly mounting cavities and the second housing 1 enclose an electronic module assembly mounting cavity (not labeled), and two through holes 30a which are communicated with the upper surface and the lower surface of the second housing 1 and are disposed in one-to-one correspondence with the two pressure inlet openings 21 are formed in the second sealing grooves. The lower end of the through hole 30a corresponding to the right chamber 4a is enlarged to form a first cavity 3b. The two diaphragm assemblies 4 are arranged in the two diaphragm assembly mounting cavities in a one-to-one correspondence. Each diaphragm assembly 4 comprises a metal diaphragm 41 and forms a chamber 4a or a chamber 4b with the second housing 1, and the upper side of the chamber 4a or the chamber 4b is correspondingly communicated with the through hole 30a. The metal diaphragm 41 is sealed off between the lower side of the chamber 4b and the pressure introduction port 21. In other embodiments, it is preferable that adjacent portions of the two circles of the second seal groove 2a are integrally connected, and likewise, adjacent portions of the two circles of the second seal flange 3a are integrally connected. Wherein, the opposite ends of the second housing 1 may be provided with mounting holes, and a bushing 13 is fixed in the mounting holes to facilitate mechanical connection with external devices.

Specifically, wherein the diaphragm assembly 4 further comprises a diaphragm mounting base 43. The sidewall of the diaphragm mounting base 43 is sealingly connected to the sidewall of the second recess 3c formed at the bottom of the housing 3. The peripheral edge is sealingly connected to a metal diaphragm 41 on a ring of bosses formed by downwardly projecting diaphragm mounting base 43. The metal diaphragm 41 and the diaphragm mounting base 43 define a chamber 4a or a chamber 4b therebetween. Each of the chambers 4a and 4b is communicated to the lower end of the corresponding through hole 30a via a hole 43a opened in the diaphragm mounting base 43, and the upper end of the hole 43a may be formed with a flared portion 43b so as to be connected with the lower end of the through hole 30 a. In other embodiments, the diaphragm assembly 4 may also include only one metal diaphragm 41, with the edges of the metal diaphragm 41 being directly sealingly connected within the housing 3. Preferably, the lower side of the edge of the diaphragm assembly 4 is welded to a pressing ring 42, so that both sides of the metal diaphragm 41 are clamped by the diaphragm mounting base 43 and the pressing ring 42, respectively, and then welded, so that the metal diaphragm is not easy to deform during welding. In other embodiments, it is preferable that the lower end of each pressure introduction port 21 is further fixed to a joint pipe 9 for facilitating connection to a container (not shown) containing a pressure medium to be measured.

The electronic module assembly 7 is disposed in the electronic module mounting chamber and is connected to an external device through a plurality of connector terminals 12b fixed to the second housing 1. By way of example only, the electronic module assembly 7 may comprise a rigid circuit board 73, one side of the rigid circuit board 73 being provided with electronic components 75 and the other side being secured by means of adhesive or the like in the electronic module assembly mounting cavity, for example, to the top inner wall of the pressure chip 6, or to the top surface of the housing 3. The hard circuit board 73 may be electrically connected to the connector terminals 12b through a flexible circuit board 74a, and to the upper ends of the connection terminals 72 through a flexible circuit board 74 b.

The two ends of the connecting pipe 8 are respectively and hermetically communicated with the upper ends of the two through holes 30a, and the cavity 4a, the cavity 4b, the through holes 30a, the first concave cavity 3b and the inner cavity of the connecting pipe 8 are communicated to form a pressure-guiding liquid filling space (not marked).

The pressure chip 6 is fixed in the first cavity 3b, and is plugged at the lower end of the corresponding through hole 30a and separates the pressure-guiding liquid filling space into a first part (not labeled) and a second part (not labeled), wherein the first sensing surface (upper side surface) is exposed in the right through hole 30a, and the second sensing surface (lower side surface) is exposed in the first cavity 3 b. The first portion and the second portion are each in communication with a lower end of a pressure-guiding fluid injection hole 32. The upper end of the pressure-guiding liquid injection hole 32 is plugged with a sealing body 31, and the sealing body 31 can be a steel ball or solder welded with the upper end of the pressure-guiding liquid injection hole 32. Preferably, the pressure-guiding injection hole 32 may be disposed on the base 3, and its upper end preferably extends into the corresponding recess 33a or recess 33 b.

The differential pressure sensor further includes a plurality of connection terminals 72. The lower ends of the connection terminals 72 extend into the first cavity 3b after passing through the housing 3 in a sealed manner and are electrically connected to the pressure chip 6 through the connection leads 71, and the upper ends thereof are electrically connected to the electronic module assembly 7. Illustratively, the base 3 is provided with a plurality of through holes (not labeled) penetrating up and down, the lower ends of the through holes extend into the first cavity 3b, and the connection terminals 72 penetrate through the through holes and are sealed with the through holes by the glass 72 a.

The pressure difference sensor transfers the first pressure of the medium to be measured received by the left metal diaphragm 41 in fig. 1 to the first sensing surface of the pressure chip 6 through the pressure guiding liquid 40b in the first part of the pressure guiding liquid filling space by the connecting pipe 8, and the second pressure of the medium to be measured received by the right metal diaphragm 41 in fig. 1 is transferred to the second sensing surface of the pressure chip 6 through the pressure guiding liquid 40b in the second part of the pressure guiding liquid filling space, so that the pressure chip 6 generates a corresponding electric signal according to the difference between the first pressure of the medium to be measured and the second pressure of the medium to be measured. Unlike the prior art, the internal cavity of the connecting tube 8 of the present solution forms part of the first portion without the need to machine elongated transverse holes in the seat 3, whereby the difficulty and cost of manufacture can be greatly reduced.

In other embodiments, the upper end of the through hole 30a is preferably enlarged to form the concave portions 33a and 33b. The both ends 8a, 8b of the connection pipe 8 are welded to the bottoms of the concave portions 33a, 33b, respectively, and surround the upper ends of the through holes 30 a. The recesses 33a, 33b may facilitate reducing the overall height of the connection tube 8. Preferably, the upper end of the through hole 30a extends to the corresponding recess 33a or recess 33b, so that the pressure guiding liquid 40b can fill the upper end of the through hole 30a and then seal the sealing body 31 at the upper end of the through hole 30a when the pressure guiding liquid 40b is poured, thereby completely filling the corresponding first portion or second portion with the pressure guiding liquid 40 b. Preferably, the bottoms of the recesses 33a and 33b are flat, which will facilitate a sealed connection of the connecting tube 8 with the bottom of the recess 33a or 33b. In this embodiment, the connection pipe 8 is preferably a metal pipe, and both ends thereof are sealed and welded with the base 3; of course, in other embodiments, the present invention is not limited to the metal tube, and may be, for example, a hose, which is sealingly bonded to the base 3 by a sealant.

As shown in fig. 2, it is further preferable that the connection pipe 8 includes a vertical portion at both ends 8a, 8b and a middle portion connecting both vertical portions. The middle part has an elastic part 81 for providing a certain elasticity for stretching left and right, and the size deviation between the left and right intervals of the two ends of the connecting pipe 8 and the left and right intervals of the two through holes 30a is compensated, so that the assembly and the welding are convenient. The intermediate portion preferably extends in a horizontal plane to minimize the overall height thereof, for example, the elastic portion 81 may be serpentine in the horizontal plane.

In other aspects, it is preferable that at least one of the one end 8a and the other end 8b of the connection tube 8 be outwardly expanded to form an expanded portion. The outer edge of the expansion part is welded to the base body 3, so that by increasing the circumference of the end portion thereof, the welding length can be increased to facilitate the welding operation, and on the other hand, the inner cavity volume of the connection pipe 8 can be relatively reduced. A filling block 5 may also be fixed in the first cavity 3b for the purpose of minimizing the volume of the pressure-inducing liquid filling space. The expansion may be a flat lug 83 as shown in fig. 2, or a tapered lug 82, the lower end radius of the tapered lug 82 being greater than the radius of the adjacent portion thereof. In particular, the pressure-guiding liquid injection hole 32 may be formed in the conical lug 82, not in the housing 3, which is advantageous in terms of reducing the difficulty of processing and the manufacturing cost. At the same time, the upper edge of the corresponding recess is flush with or higher than the upper end of the pressure-guiding liquid injection hole 32, which facilitates complete discharge of air in the corresponding portion of the pressure-guiding liquid filling space to fill the pressure-guiding liquid 40b.

In the above embodiment, in order to enable complete evacuation of air in the connection pipe 8, a receiving groove (not shown) may be provided in the top 34 of the housing 3 to facilitate receiving the connection pipe 8, and the top height of the inner cavity of the connection pipe 8 may be relatively lowered, preferably lower than the upper end of the corresponding pressure-guiding liquid injection hole 32, so that the rigid circuit board 73 may be further conveniently adhered to the top 34. Or when the pressure guide 40b is poured, the pressure sensor is inclined at a certain angle, and the upper end of the pressure guide injection hole 32 is higher than or flush with the top of the inner cavity of the connecting pipe 8.

The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims

1. A differential pressure sensor, comprising:

A first housing (2) provided with two pressure inlets (21) for introducing a pressure medium at right and left intervals;

A second housing (1) connected to the first housing (2) in a downwardly sealed manner and enclosing a mounting cavity therewith;

A base body (3) which is connected to the first shell (2) in a downward sealing way and is arranged in the mounting cavity, wherein the lower side of the base body and the first shell enclose two diaphragm assembly mounting cavities which respectively correspond to the two pressure introduction ports (21) downwards, the upper side of the base body and the second shell (1) enclose an electronic module assembly mounting cavity, two through holes (30 a) which are communicated with the upper surface and the lower surface of the second shell (1) and are arranged in a one-to-one correspondence with the two pressure introduction ports (21) are formed in the base body, and the lower end of one through hole (30 a) is enlarged to form a first concave cavity (3 b);

The two diaphragm assemblies (4) are arranged in the two diaphragm assembly mounting cavities in a one-to-one correspondence manner, and comprise a metal diaphragm (41), a cavity (4 b) is defined between the metal diaphragm and the second shell (1), the upper side of the cavity (4 b) is correspondingly communicated with the through hole (30 a), and the metal diaphragm (41) is sealed and separated between the lower side of the cavity (4 b) and the pressure inlet (21);

An electronic module assembly (7) disposed in the electronic module mounting chamber and connected to an external device through a plurality of connector terminals (12 b) fixed to the second housing (1);

The two ends of the connecting pipe (8) are respectively communicated with the upper ends of the two through holes (30 a) in a sealing way, and the cavities (4 b), the through holes (30 a), the first concave cavity (3 b) and the inner cavity of the connecting pipe (8) are communicated to form a pressure guide liquid filling space;

a pressure chip (6) fixed on the first concave cavity (3 b), which is blocked at the lower end of the corresponding through hole (30 a) and separates the pressure-guiding liquid filling space into a first part and a second part, wherein the first part and the second part are respectively communicated with the lower end of a pressure-guiding liquid (40 b) filling hole (32), and a sealing body (31) is blocked at the upper end of the pressure-guiding liquid (40 b) filling hole (32);

And a plurality of connection terminals (72) which extend into the first cavity (3 b) after penetrating through the base body (3) in a sealing manner at the lower end and are electrically connected with the pressure chip (6), and are electrically connected with the electronic module assembly (7) at the upper end.

2. Differential pressure sensor according to claim 1, characterized in that the upper end of the through hole (30 a) is enlarged to form a recess (33 a, 33 b), the two ends (8 a, 8 b) of the connecting tube (8) being welded correspondingly to the bottom of the recess (33 a, 33 b) and surrounding the upper end of the through hole (30 a).

3. Differential pressure sensor according to claim 1, characterized in that the connecting tube (8) comprises a vertical portion at both ends (8 a, 8 b) and a middle portion connecting the two vertical portions, the middle portion having an elastic portion (81) providing a certain elasticity for stretching left and right.

4. A differential pressure sensor as claimed in claim 3, wherein the intermediate portion extends in a horizontal plane.

5. Differential pressure sensor according to claim 4, characterized in that the elastic portion (81) is serpentine-shaped.

6. Differential pressure sensor according to claim 1, characterized in that at least one of the two ends (8 a, 8 b) of the connecting tube (8) is flared (8 a/8 b) to form a flared portion, the outer edge of which is welded to the seat (3).

7. The differential pressure sensor of claim 6, wherein the expansion is a flat tab (83).

8. The differential pressure sensor of claim 6, wherein the expansion portion is a tapered tab (82), a lower end radius of the tapered tab (82) being greater than a radius of an adjacent portion thereof.

9. The differential pressure sensor of claim 7, wherein the pilot fluid (40 b) injection hole (32) is formed in a conical tab (82).

10. The differential pressure sensor of claim 7, wherein the diaphragm assembly (4) further comprises a diaphragm mounting base (43), a side wall of the diaphragm mounting base (43) being sealingly connected to a side wall of a second cavity (3 c) formed in the bottom of the seat body (3), and a peripheral edge being sealingly connected to a metal diaphragm (41) on a ring of convex rings formed by downward projection of the diaphragm mounting base (43); a cavity (4 b) is defined between the metal diaphragm (41) and the diaphragm mounting base body (43), and each cavity (4 b) is communicated with the lower end of the corresponding through hole (30 a) through a hole (43 a) formed in the diaphragm mounting base body (43).